1. Field of the Present Invention
The present invention relates to a method of stacking a flexible substrate, and more particularly, to a method of fabricating a flexible substrate capable of preventing bending of the flexible substrate without modification of production lines of conventional semiconductor and display devices.
2. Discussion of Related Art
As modern society is becoming increasingly information-oriented, the importance of the display unit, which enables visualization of various types of information output from various devices, is increasing. Moreover, this trend is expected to continue for some time. As the information revolution progresses, the demand for information increases proportionately. In the field of displays, which are man-machine interfaces for information delivery, research aimed at enabling viewing without constraints and expressing true colors and the full intricacy of nature is actively progressing.
In general, displays have been widely adapted in TVs, monitors and mobile phones. However, as technology develops, there is increasing demand for displays that are small, lightweight, have wide views, superior resolution, and fast response times. In reaction to such demand, efforts have been stepped up to enlarge displays and reduce the density and thickness of their glass substrate.
However, such efforts cause problems in ensuring processability and reliability, and thus technological limits are confronted. An additional problem is that downsizing of display devices for portability clashes with consumers' desire for widescreen displays. Thus, in order to simultaneously obtain superior flexibility, light weight, and portability, a need has arisen for a flexible display substrate in which interconnections and elements of the display are formed on a flexible substrate.
However, when using a flexible substrate to form an image display device, a difference in coefficient of thermal expansion between the flexible substrate and a carrier substrate may result in the application of stress to an adhesive layer joining the two substrates in a high temperature process (150-250° C.). An additional problem is that, because it lacks rigidity, the flexible substrate cannot be processed by conventional semiconductor manufacturing equipment or by display manufacturing equipment for liquid crystal displays and e-paper. So, it is necessary to either develop special equipment or drastically modify the conventional manufacturing equipment. Existing display set providers such as Sharp and Phillips have invented a chuck for a flexible display and applied it to a conventional manufacturing process. However, this method leads to difficulties in mass-production and processing and, consequently, higher production costs.